1. Field of the Invention
The present invention relates to a sheet transport direction switching device for switching a transport direction of a sheet to be transported, and an image forming apparatus incorporated with the sheet transport direction switching device.
2. Description of the Related Art
Conventionally, there is known a sheet transport direction switching device, as recited in JP Hei 9-86759A, for use in a sheet transport system in an image forming apparatus. The sheet transport direction switching device is operable to switch a discharge destination of a sheet subjected to an image forming operation and carrying a toner image on a surface thereof between a discharge tray and a switchback path for a double-side printing operation, and a rotary guide member is provided at a branching position of the two destinations.
The rotary guide member is constituted of a pair of circular side plates disposed opposite to each other with a distance slightly larger than a sheet width, four guide plates mounted between the circular side plates, and rotating shafts extending in directions opposite to each other from the circular side plates. Three guide passages i.e. a middle straightforward guide passage, and two inverse guide passages defined at both sides of the middle straightforward guide passage are defined between each opposing pair of the guide plates. A sheet transported to the rotary guide member is selectively passed through one of the guide passages depending on a rotated amount of the rotary guide member with respect to a reference position thereof. The sheet is discharged to a predetermined destination depending on the selected guide passage.
The rotary guide member has such a complicated structure that the plural guide plates are mounted between the paired circular side plates. Accordingly, the material cost may be increased due to a large number of parts.